The present invention is directed to an orthopedic instrument in general, and in particular to a fastening or crimping device for use with surgical cables in fixation of bones during surgeries for fractured bone or bone reconstruction.
In surgical and orthopedic operative techniques, it is frequently necessary to fix bone parts, which have been separated surgically or because of fracture, in an exact mutual position and to join them together under pressure. Surgical cable and crimp assemblies are frequently used for this purpose. The cables are used to encircle the bone, or bone and plate, to provide for fixation. In fixation by cable, it is customary to use a fastening device, typically a crimp device which is adapted to be deformed upon the cable for securing the cable in place, encircling the bone in the fracture area. Such assemblies can be subjected to very high tensile forces when, for example, the fractured bone is subjected to a high bending moment. It is therefore important that the cable and crimp assembly have sufficient strength to prevent cable failure under tensile force.
Typically, the cable must be used in a subcutaneous confined area. Thus it is important that the cable and crimp assembly be easy to assemble in such a restricted area. For instance it is desirable to have a device which allows the cable to pass easily through the crimp member to prevent kinking and possible fraying of the cable where it enters the crimp member. Also it is advantageous to have easy access to the crimp device to facilitate crimping. Easy cable access is also desirable to provide room for the application of a tension tool to tighten the cable around the bone. Furthermore, it is desirable to maintain the bulk of the cable as well as the joint where the cable is affixed to itself as compact as possible to minimize discomfort to the patient and damage to the surrounding tissue.
A wide variety of devices for crimping a surgical wire are known in the art. Examples of such crimp devices include those described in U.S. Pat. No. 5,810,825 issued to Huebner, U.S. Pat. Nos. 5,868,748 and 5,720,747 to Burke. Although these devices are quite successful from a technical point-of-view in achieving the desired crimping of surgical wire, most of existing devices have practical limitations. For example, most crimping devices maintain the surgical wire or cable parallel to itself in the fastening or crimping member which makes it difficult to access the free end of the cable and tighten around the bone. In addition, some crimping devices require that the entire fastening or crimping member be crimped in order to secure the surgical wire thereto, necessitating a larger access area to permit a crimping tool to access the entire fastening or crimping member.
Other crimp devices exist which are substantially xe2x80x9cLxe2x80x9d shaped and maintain the surgical wire or cable at a 90xc2x0 angle to itself as it leaves the fastening or crimping member. Maintaining the cable at such a steep angle can put a kink in the cable at that location and increase the likelihood that the cable will break. Furthermore, when the crimping member maintains the cable at a 90xc2x0 angle, it is more difficult to insert the cable through the crimp member.
Thus, there exists a need for an improved surgical crimp device that is compact, sufficiently strong, and easy to assemble in a confined area.
The present invention is directed to a surgical fastener device for fixing bone elements comprising a flexible cable having first and second ends attached to a crimp member. The crimp member has first and second portions extending between front and rear ends. First and second portions are spaced farthest apart at the rear end to form a wedge-shaped. Additionally, a channel extends through the second portion. The first end of the cable is fixedly secured to the first portion at the rear end, and the second end of the cable is insertable through the channel of the second portion for forming a loop of adjustable diameter.
In one embodiment, the front and rear ends of the crimp member are rounded and the front end of the crimp member can have a smaller arc length than the rear end.
In another embodiment, the front end of the crimp member is solid and the rear end has a longitudinal slot.
In yet another embodiment, the crimp member has an open central portion that forms a substantially triangular cutout.
In an alternative embodiment, the second end of the cable has a leader to facilitate handling.
In an additional embodiment, the cable is multi-stranded.
In another embodiment, the first and second portions of the crimp member are coplanar.
The present invention is further directed to a surgical fastener device for crimping surgical cable. The device includes a crimp member comprising a wedge-like body having first and second parallel major surfaces vertically interconnected by a peripheral edge. The body has a centrally disposed triangular opening vertically extending through the body from the first major surface to the second major surface. The body also has a pair of channels extending longitudinally through the body. The channels are disposed at a non-parallel angle with respect to each other.
In an alternative embodiment, the device further includes a flexible cable secured to one of the channels of the crimp member. The cable has first and second ends and one end is fixedly attached to the crimp member and the other end is insertable through the other channel for forming a loop of adjustable diameter. The cable can be multi-stranded and the insertable end can have a leader to facilitate handling.
The present invention is also directed to a surgical fastening device comprising a cable having a free end and a fixed end attached to a crimp member. The crimp member has a first leg with first and second ends. The first end has a blind hole for receiving the fixed end of the cable. The crimp member also has a second leg with first and second ends. The second leg has a through bore extending from the first end to the second end of the second leg. The crimp member also has a front bridging portion connecting the second end of the first leg to the second end of the second leg. The crimp member also has a rear bridging portion connecting the first end of the first leg to the first end of the second leg. The rear bridging portion is longer than the front bridging portion so that the crimp member has a wedge-shape. The second leg is crimpable so that the cable is crimped to the crimp member after the free end is inserted in the through bore.
In another embodiment, the cable is multi-stranded and the free end has a leader to facilitate handling.